Switch to stdbool.h

- Add `#include <stdbool.h> to all files previously using the
   `TRUE`/`FALSE` macros
 - Replace all instances of `TRUE`/`FALSE` with `true`/`false`,
   respectively
 - Definitions of `TRUE`/`FALSE` macros retained in wiringPi.h for compatibility.

examples/PiFace/ladder.c

@@ -7,17 +7,13 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdbool.h>
 #include <unistd.h>
 #include <math.h>
 
 #include <wiringPi.h>
 #include <piFace.h>
 
-#ifndef	TRUE
-#  define	TRUE	(1==1)
-#  define	FALSE	(1==2)
-#endif
-
 #undef	DEBUG
 
 #define	NUM_LEDS	 8
@@ -244,7 +240,7 @@ void ledOnAction (void)
   if (digitalRead (PIFACE) == LOW)
   {
     chargeCapacitor () ;
-    ledBargraph (vCap, TRUE) ;
+    ledBargraph (vCap, true) ;
   }
 }
 
@@ -264,7 +260,7 @@ void ledOffAction (void)
   if (digitalRead (PIFACE) == LOW)
   {
     vCap = vCapLast = 0.0 ;
-    ledBargraph (vCap, FALSE) ;
+    ledBargraph (vCap, false) ;
 
 // Wait until we release the button
 
@@ -300,7 +296,7 @@ int main (void)
 
 // LED ON:
 
-    (void)ledBargraph (vCap, TRUE) ;
+    (void)ledBargraph (vCap, true) ;
     then = millis () + ledOnTime ;
     while (millis () < then)
     {
@@ -323,7 +319,7 @@ int main (void)
 
 // LED OFF:
 
-    (void)ledBargraph (vCap, FALSE) ;
+    (void)ledBargraph (vCap, false) ;
     then = millis () + ledOffTime ;
     while (millis () < then)
     {